Pressure cooker closure



1961 H. F. swANsoN 2,966,999

PRESSURE COOKER CLOSURE Filed Jan. 5, 1959 2 Sheets-Sheet 1 \\\&

13 INVENTOR. HERBERT F. SWANSON Jan. 3, 1961 Filed Jan. 5, 1959 H. F;SWANSON 2,966,999

PRESSURE COOKER CLOSURE 2 Sheets-Sheet 2 INVENTOR.

AM 6%, WM v ATTORNEY? HERBERT F. SWANSON iii PRESSURE COGKER CLOSUREHerbert F. Swanson, Chicago, Ill., assignor to General Electric Company,a corporation of New York Filed Jan. 5, 1959, Ser. No. 735,077

Claims. (Cl. 220-25) This invention relates generally to cookingapparatus such as pressure cookers, and more particularly to an improvedclosure and mounting for a pressure cooker.

In pressure cookers provided with a cooking chamber having an openingfor the insertion and removal of a product processed within the chamber,the premature opening of the closure at the end of the cookingoperation, that is, before the steam pressure within the chamber hasbeen permitted to drop to a low level, may permit the residual steamwithin the cooking chamber to escape too rapidly, sometimes with injuryto the operator. Where the closure opens outwardly, such residualpressure within the vessel may actually be effective to move the closurewith what may be explosive force. In the invention herein, the closureis moved inwardly against the pressure within the vessel; and theinitial opening movement thereof, which occurs after the release of alatch for the closure, is achieved by a pair of relatively lightsprings, the bias of which must be greater than the total force againstthe closure before the closure will disengage from its seat about thechamber opening. The springs cooperate with pivotally mounted supportarms for the closure. Said support arms have a lost motion connectionwith respect to pivot studs projecting from walls of the chamber,whereby upon release of the latch, the springs draw the closure directlyrearwardly. After this initial opening movement of the closure iscompleted, counterbalancing springs complete the pivotal movement of theclosurecarrying arms to a position establishing the'closure in aposition permitting the removal of pans of the foodstufi or the likewhich had been processed within the chamber.

It is a general object of this invention to provide an improved closurefor a pressure cooker, such closure being so mounted that its initialmovement in an opening direction is inward and against the residualpressure within the cooker, such initial movement providing a smallannular passage around the closure forthe escape of residual pressure,and being so mounted that upon its further movement it is positioned toone side within the cooking chamber, so that the contents therein canreadily be removed.

Another object is to provide an improved closure for a pressure cooker,said closure being removably mounted on a support mechanism which givesto the closure an initial rearward movement from its seat into thecooking chamber, such initial movement beingto an extent .providing anarrow annular passageway for the escape of residual steam, whileprotecting the operators hand against being scalded; said supportmechanism also providing for easy further movement of the closure intothe chamber to a fully opened position.

Another object is to provide an improved pressure cooker characterizedby a cooking chamber havingran opening and a closure therefor, theclosure having a latching structure maintaining the closure in latchedposition against a closure seat at the opening, the closure moving aslight distance from its seat upon initial operation of the latchingstructure to provide a passageway through which residual steam in thecooking chamber can escape, the closure amass Patented Jan. 3, 1961being subsequently movable upon further operation of the latchingstructure to a position within the chamber where the contents thereofmay readily be removed.

Yet another object is to provide a closure for a pressure cooker, saidclosure being initially movable a small distance into the chamberlongitudinally of the opening by reason of a lost motion support for theclosure and a spring biasing the closure inwardly, the closure beingsubsequently pivotable about its support to a fully opened position.

Further features of the invention pertain to the particular arrangementof the elements comprising a closure for the pressure cooker and thesupport therefor, whereby the above outlined and additional featuresthereof are attained.

The invention, both as to its organization and method of operation,together with further objects and advantages thereof, will best beunderstood by reference to the following specification taken inconnection with the accompanying drawings, in which:

Fig. 1 is a perspective view of a pressure cooker embodying theimprovements according to the present invention;

Fig. 2 is a vertical section taken through the pressure cooker of Fig.l, substantially along the plane 22 of Fig. 1 and looking in thedirection of the arrows, certain parts being shown in elevation;

Fig. 3 is a view similar to Fig. 2, but showing the operation of a latchfor the closure of the pressure cooker seen in Fig. 1, showing the latchand closure during their initial operating movement;

Fig. 4 is a view similar to Fig. 3, but showing the closure and thelatch in a position where the contents of the pressure'cooker canreadily be removed;

Fig. 5 is a horizontal section taken along the line 55 of Fig. 2 lookingin the direction of the arrows;

Fig. 6 is an enlarged detailed sectional view of the support for theclosure seen in Figs. 2 to 5 inclusive; and

Fig. 7 'is a phantom perspective view showing how the closure isdetachably secured to its support arms, so that it can be removedtherefrom for cleaning of both the interior of the cooker and itsclosure.

Referring now particularly to Figs. 1 to 4 of the drawings, the pressurecooker 10 according to the present invention includes a housing lihaving a base 12 adapted to rest upon feet 13. Opposed side walls 14 ofthe housing 11 extend from the base 12, and a top 15 extends between theside walls 14.- The housing 11 also comprises a front wall 16 and a rearwall 17 spaced from the front'wall 16.

The housing 11 thus far described encloses a walied pressure vessel 18including top and bottom walls 19 and 21, side walls 22 and 23 and anend wall 24, defining a cooking chamber 20. In a presently manufacturedform, the pressure vessel operates at an internal steam pressure of 15pounds per square inch, gauge. The front wall 26 of vessel 18 has anopening 27 therein which is aligned with an opening 28 in the front wall16 of the housing 11. Suitable insulating material 29 is providedbetween the walls of the vessel 18 and the housing 11, and the vessel 18is appropriately supported within the housing 11 in spaced relationshipthereto by means including the insulating material 29.

Provision is made for heating of the contents within the walled vessel18, and consists of a heating element 31, preferably of the sheathedresistance conductor type. Heating element 31 is connected by leads 32to control elements of a control group 33 disposed on the front panel16. Said control elements provide for theconof electric power.

The opening 27 for the walled vessel 18 has a seat 34 for a closure 36,the closure 36 having the periphery thereof fitted with gasket material37 of a U-shaped cross section with spaced limbs 38 embracing theclosure 36. As seen in the several views, the closure 36 is in the formof a shallow dish, substantially rectangular in shape, with its cornersrounded as at 46, see Fig. 7, to correspond to rounded corners 39 of theopening 28 in housing 11.

Structure is provided 'for latching the closure 36 into position firmlyagainst the seat 34 of the vessel 13, and to this end the closure 36 hasa U-shaped bracket 41 suitably permanently afiixed to the front sidethereof, the spaced limbs 42 of the U-shaped bracket 41 being straddledby a lever '43 pivotally connected by a pin to the U-shaped bracket 41.The lever 43 has its other end provided with a latch member 46 pivotallyconnected by a pin 47 thereto. The latch member 46 terminates in anoperating knob 43, and has a cam-like latching surface 49 cooperatingwith a pin 51 straddling spaced lugs 52 of a fixed latch abutment 53secured to the front panel 16 below the opening 28. A stud 53a at theupper portion of abutment 53 is engageable by the wall portion 43a oflever 43 to provide a fulcrum about which lever 43 pivots during openingand closing movements thereof.

As seen in Fig. 2, when the latching surface 49 is engaged with the pin51, and the latch member 46 is rocked in a clockwise direction, lever 43will be rocked in a counter-clockwise direction about stud 53a. closure36 being secured in position against the seat 34 at the end of thelatching operation described. The cam shape of the latching element 49multiplies the mechanical advantage of the latching lever system,reduces the manual effort required to pivot the lever 43counterclockwise about stud 53a during the latching operation, andimproves the control by the operator during the unlatching operation. aslater described. Preferably stud 53a is a s rew-threaded p rt,permitting its axial adjustment relative to abutment 53.

Structure is provided fo mo ement of the closure 36 inward of the enin27 in chamber 26 to a limited degree in a direction normal to t e lonitud al axis of the open n s 27 and 28 noon i itial unl tching mo ementof the latch member 46. Such movement of the closure 36 is inward intothe chamber 20 ag inst residual pressure therein. S ch l m ted movementof the c osure 36 provi es an annu ar pas a eway past the seat 34 andaround the gas t 37. for the esc pe f residual steam from chamber 20 ofthe vessel 18. The clos re 36 is mounted for such movement upon aU-shahed c rr er 54, see Fi s. and 7. havin a sh rt ton ue 56 weldedthereto at its center. The tongue 56 cooperates w th and extends beneatha clip 55 we ded at 55a to the ins de face of l su e 36. As seen in Fi7. the closure 36 is thus separ b e from the car ier 54 so that it canbe removed for clean n or the l e, as well as the cleaning of theinterior of the vessel 18.

The carrier 54 is essentially rigid and extends along the inner side ofthe closure 36. being bent bevond the periphery thereof. as seen in Fig.5, to provide a pair of spaced arms 57. Each of the arms 57 is supportedon its end remote from t e closure 36 on a stud 58 tapped into a boss59, see Fig. 6, extending inward from side walls 22 and 23 of the vessel18.

The arms 57 each have a slot 66 provided therein to give a lost motionconnection with the stud 58, and each of the arms 57 is slidablydisposed within a guide 61 comprising the spaced plates 63 and 64, plate63 pivoting at 66 upon the stud 58, and plate 64 pivoting at 67 upon theboss 59. The two plates 63 and 64 are held together at their endsadjacent the boss 59 and the pin 58 by a pair of pins 68, Fig. 3.Similar paired pins 76 hold the plates 63 and 64 together at their otherends. It will be noted that the paired pins 68 and 70 form 4 upper andlower bearings for the arm 57 positioned between the plates 63 and 64.

The carrier 54 is rearwardly biased by a spring 71 at each of the arms57. Each spring 71 is anchored at one end to its associated arm 57 at abracket 69 riveted thereto, and at its other end about a grooved seat 72provided in the stud 58, Fig. 6. Upon initial unlatching movement of thelatch 46, the bias of springs 71 will move closure 36 rearwardly whenthe force exerted against closure 36 by the residual pressure within thechamber is less than one-tenth of a pound per square inch. This inwardmovement permits the closure to be swung upwardly to the fully openposition of Fig. 4 without interference from the top wall of thechamber.

Structure is provided for enabling the closure 36 together with itslatch consisting of the lever 43 and the latch member 46 to be moved toa position within the vessel 18 after theresidual steam has beenreleased by the movement of the closure 36 just described. The closure36 then occupies a position, as seen in Fig. 4, above racks 73 extendingbetween support members 74 extending inward from the side walls 22 and23 of the vessel 18.

In order to rock the closure 36 to a position seen in Fig. 4, eachcarrier guide 61 is provided with an ear 76 furnishing a point ofanchorage for a spring 77 having its other end anchored to a boss 78extending inward from the side walls 22 and 23 of the vessel 18. Thebias of the spring 77 is such that when the latch 43, 46 has beencompletely disengaged from the pin 51, see Figs. 3 and 4, the spring 77will swing the mounting arms 57, 57 about the pins 58, see Fig. 6,moving the closure 36 and latch 43, 46 to the position seen in Fig. 4above the racks 73.

The outwardly spiraling contour of the latching element 49 permits theclosure to move rearwardly of the chamber opening to substantially themaximum extent permitted by the lost motion mounting of the carrier arms57, before the tip of the latching member has cleared the pin 51. Thesprings 71 cannot swing the closure upwardly until the disengagement ofthe latch element from the pin, in view of the upward and rear wardmovement of the closure, whereupon the initial opening movement of theclosure is essentially horizontally rearward. It will be appreciatedthat the springs 71 are at maximum tension as the arms 57 assume theirhorizontal position, and that the forward movement of the arms cannotincrease the tension. The angle of effort of the springs 71 relative tothe arms in their horizontal position is such that the co-unterbalancingeffort of the closure and its carrier, when the closure nears its homeposition against the opening, substantially overcomes the bias ofsprings 71, whereas the reduction in the eifective length of arms 57 asthe closure attains maximum withdrawn position reduces the overbalancingeifort of the closure and its carrier to render springs 71 capable ofinitiating the upward swinging movement.

With the parts in the position seen in Fig. 4, the racks 73 can beloaded or unloaded, trays 79 being supported upon the racks 73 withineasy reach by the operator, since the closure 36 and its latch 46 areout of the way. It will be noted also that the support for the closureand its latch consisting of the arms 57 are oif to each side of theracks 73, as seen more clearly in Fig. 5.

Assuming foodstuffs to be in the chamber for processing and the closure36 latched in its sealing position, the operator initiates operation ofthe cooking apparatus by manipulating appropriate ones of the controlgroup 33, whereupon the heating unit 31 is energized and, after apredetermined interval, water is introduced directly into the chamberthrough means including a spray head 80, supplied With cold water by wayof a conventional solenoid valve 81 connected by conduit 82 to anexternal water source (not shown). The water impinging on the heatedlower wall 21 of the chamber flashes into steam,

the formation of which serves initially to purge the chamber of airthrough the temporarily opened vent line 83 communicating with theexternal atmosphere by way of solenoid-operated venting means (notshown), wellknown in the pressure cooker art. After a brief intervalcalculated to exhaust the air from the chamber, the venting means closeand the cooking period commences under control of suitable time-cyclemeans.

Upon the expiration of the predetermined cooking time, the venting meansreopen to permit the steam to escape. It will be obvious that inaddition to the locking effort exerted on the closure 36 by thecounterclockwise rota-. tion of the latching lever 43 about the pivotstud 53a as the handle 46 comes into its home position, shown in Fig. 2,the steam pressure within the chamber serves also to seat the closure.It will also be obvious that at the end of the cooking operation, it ispossible to swing the handle to a substantially horizontal position inwhich the end of the latching cam member 49 is actually disengaged fromthe latching pin 51 without the unseating of the closure 36 so long asthe steam pressure exerted by the steam against the closure 36overpowers the biasing effort of the springs '71. It is, of course, notpossible for the springs 77 to raise the closure until springs 71 havedrawn the closure carrier sufiiciently rearwardly to disengage theclosure from the seat 34, whereupon it is evident that the closure canattain its fully open position only after the pressure within thechamber has been reduced to approximately atmospheric level.

From the foregoing description, it is believed evident that there hasbeen provided an improved pressure cooker wherein the closure can beopened a slight amount by initial movement of the latch therefor, theinitial movement of the latch providing an annular passageway around theclosure to safely complete the venting of residual steam at not toorapida rate. Where residual steam escapes from the vessel by the initialmovement of the closure 36 from its seat, the operators hand at thelatch handle 48 is in a position where it cannot be scalded. The furtheroperation of the latch enables the closure 36 to move to a position outof the way of the opening to the housing, and the opening to the vesselsupported within the housing, so that the contents within the vessel canbe readily removed therefrom.

While there has been described what is at present considered to be thepreferred embodiment of the invention, it will be understood thatvarious modifications may be made therein, and it is intended to coverin the appended claims all such modifications as fall within the truespirit and scope of the invention.

What is claimed is:

1. In a pressure cooker, a walled vessel defining a cooking chamber, anopening for said vessel including a seat in said opening, a closure forsaid vessel adapted to engage said seat, latching means maintaining saidclosure in engagement with said seat, means for carrying said closureincluding spaced arms extending from said closure, pivot means extendingfrom the walls of said vessel for pivotally supporting said armsrelative thereto, a lost motion connection between each of said arms andits pivot means for moving said closure inward of the opening in saidchamber and from said seat an initial distance against the residualpressure in said chamber upon initial movement of said latching means inan unlatching direction comprising spring means connected between saidspaced arms and the supports therefor and operable to take up the lostmotion connection of said arms, said spring means having a bias which isgreater than the total force against said closure resulting from theresidual pressure in said chamber following a cooking operation, guidemeans slidably receiving the respective arms, said guide means beingrotatably mounted on the said pivot means, and means for moving saidclosure away from said opening by pivotal movement thereof about saidpivot means upon completion of the unlatching movement of said latchingmeans, including spring means connected between said guide means andsaid walled vessel.

2. In a pressure cooker having structure providing an enclosedfood-processing chamber having an end-wall opening afiording accessthereinto, the combination comprising a closure for said opening, meansfor mounting said closure for operation between open and closedpositions, said mounting means including structure providing arm membersextending along opposite side walls of said chamber, guide means forreceiving an end portion of each of said arm members for predeterminedmovement of said arm members longitudinally of said chamber, means forpivotally mounting said guide means for rotation within said chamber,means for biasing said arm members into movement inwardly of saidchamber, latch means secured to said closure for drawing the same intochamber-closing position against the effort of said biasing means, andspring means for rotating said guide means and therein-received armmembers to operate said closure to fully-opened position upon release ofsaid latch means.

3. In a pressure cooker having structure providing an enclosedfood-processing chamber having an end-wall opening affording accessthereinto, and a closure for said opening; a closure carrying andoperating means comprising a U-shaped structure secured at its bight tosaid closure and having arm members extending rearwardly thereofadjacent opposite side walls of said chamber, tubular members forslidably receiving an end portion of each of said arm members, means forestablishing predetermined limits of movement of said arm membersrelative to said tubular members, means for biasing said arm memberstoward one of said limits of movement, means for mounting said tubularmembers for rotation within said chamber, latch means for drawing saidclosure-carrying structure in opposition to said biasing means toreleasably position the closure in chamberclosing position, and springmeans engaging said tubular members to rotate said members and the saidU-shaped structure carried thereby to establish the closure in fullyopenposition upon release of said latch means and movement of saidclosure-carrying structure to the said one limit of movement of said armmembers relative to said tubular members.

4. In a pressure cooker having structure providing an enclosedfood-processing chamber having an access opening, a closure for saidopening, said closure being wholly within said opening, and latch meansfor releasably securing said closure in chamber-sealing position; aclosure carrying and operating means comprising structure releasablyengaging said closure and having rigid, strap-Like, arm portionsextending adjacent opposite side walls of said chamber, pivot meansprojecting into said chamber from the said side walls thereof, meansrotatably mounted on each of said pivot means for supporting therespective arm portions for longitudinal and rotational displacementwithin said chamber, said supporting means each including at least oneplate member in facing relation with a side of the associated armportion and upper and lower bearing elements extending from said platemembers transversely across the respective upper and lower surfaces ofsaid arm portions whereby the said arm portions are guided forlongitudinal movement, spring means between said arm portions and saidsupport means for urging said closure-carrying structure inwardly ofsaid chamber, spring mounting means disposed within said chamber invertically and longitudinally spaced relation to said pivot means, andsecond spring means extending between said spring mounting means andsaid arm portion supporting means to urge the latter into rotation,whereby upon release of said latching means the first-named spring meanswill move the closure carrying structure longitudinally inwardly of saidchamher and said second spring means will rotate said closure 7 carryingstructure relative to said chamber access opening.

5. The combination according to claim 4, in which each of said armportions slidably embraces the pivot means associated with itssupporting means to establish fixed limits of the longitudinal movementof said arm portions relative to the supporting means.

6. A pressure cooker, comprising a walled vessel defining a cookingchamber for operation at substantial internal steam pressure andprovided with an opening thereinto having a surrounding seat, a door forsaid opening, said door having a closed position with respect to saidopening engaging said seat and positioned in said chamber closelyadjacent to said opening, said door having apartialiy open position withrespect to said opening disengaging said seat and positioned in saidchamber a predetermined distance inwardly of said opening, said doorhaving a fully open position with respect to said opening disengagingsaid seat and positioned in said chamber substantially out of alignmentwith said opening and disposed closely adjacent to one of the walls ofsaid vessel, latching means releasably maintaining said door in itsclosed position, a carrier for said door including arms extendingtherefrom and guides movably supporting said arms, means pivotalymounting said guides upon supports secured to the walls of said vessel,a lost-motion connection between said arms and said guides andestablishing said predetermined distance in the movement of said doorbetween its closed position and its partially open position, "firstspring means acting between said arms and said guides for moving saidarms upon said guides in order to move said door from its closedposition into its partially open position upon initial movement of saidlatching means in an unlatching direction, and second spring meansacting between said carrier and the walls of said vessel for pivotingsaid carrier upon said supports in order to move said door from itspartially open position into its fully open position upon final movementof said latching means in an unlatching direction.

7. The pressure cooker set forth in claim 6, wherein said arms areslidably supported by said guides, and said door in its partially openposition is disposed substantially in alignment with the longitudinalaxis of said opening.

8. A pressure cooker, comprising a walled vessel defining a cookingchamber for operation at substantial internal steam pressure andprovided with an opening thereinto having a surrounding seat, a door forsaid opening, said door having a closed position with respect to saidopening engaging said seat and positioned in said chamber closelyadjacent to said opening, said door having a partially open positionwith respect to said opening disengaging said seat and positioned insaid chamber a predetermined distance inwardly of said opening, saiddoor having a fully open position with respect to said openingdisengaging said seat and positioned in said chamber substantially outof alignment with said opening and disposed closely adjacent to one ofthe walls of said vessel, latching 'r'neans releasably maintaining saiddoor in its closed position, a carrier for said door including armsextending therefrom and guides movably supporting said arms, meanspivotally mounting said guides upon supports secured to the walls ofsaid vessel,

the movement of said door between its closed position and its partiallyopen position, first spring means acting between said arms and saidguides for moving said arms upon said guides in order to move said doorfrom its closed position into its partially open position against theresidual pressure in said chamber upon initial movement of said latchingmeans in an unlatching direction, said first spring means having a biaswhich is greater than the total force against said door resulting fromthe residual pressure in said chamber, and second spring means actingbetween said carrier and the walls of said vessel for pivoting saidcarrier upon said supports in order to move said door from its partiallyopen position into its fully open position upon final movement of saidlatching means in an unlatching direction.

9. The pressure cooker set forth in claim 8, wherein said first springmeans has a bias which is greater than the total force against said doorresulting from a residual pressure in said chamber of one-tenth poundper square inch gauge, whereby the movement of said door from its closedposition into its partially open position completes the dissipation ofsteam pressure within said chamber following a food processingoperation.

10. A pressure cooker, comprising a walled vessel defining a cookingchamber for operation at substantial internal steam pressure andprovided with an opening thereinto having a surrounding seat, a door forsaid opening, said door having a closed position with respect to saidopening engaging said seat and positioned in said chamber closelyadjacent to said opening, said door having a partially open positionwith respect to said opening disengaging said seat and positioned insaid chamber a predetermined distance inwardly of said opening, saiddoor having a fully open position with respect to said openingdisengaging said seat and positioned in said chamber substantially outof alignment with said opening and disposed closely adjacent to one ofthe walls of said vessel. latching means releasably maintaining saiddoor in its closed position, a carrier detachably connected to saiddoor, said carrier including arms extending therefrom and guides movablysupporting said arms, means pivotally mounting said guides upon supportssecured to the walls of said vessel, a lost-motion connection betweensaid arms and said guides and establishing said predetermined distancein the movement of said door between its closed position and itspartially open position,

first spring means acting between said arms and said References Cited inthe file of this patent UNITED STATES PATENTS Pledger Nov. 2, 1948Binding Feb. 10, 1953

